"""Property-based tests for location permission functionality.

Feature: buyu-walking-app
Testing correctness properties related to location permissions.
"""
import pytest
from hypothesis import given, strategies as st, settings, assume
from unittest.mock import Mock, patch, MagicMock
import uuid


# Strategies for generating test data
@st.composite
def permission_grant_event(draw):
    """Generate a permission grant event."""
    return {
        'user_id': draw(st.uuids()).hex,
        'permission_type': 'location',
        'granted': True,
        'timestamp': draw(st.datetimes()),
        'reason': draw(st.sampled_from([
            'granted_first_time',
            'granted_after_explanation',
            'granted_in_settings',
            'already_granted'
        ]))
    }


@st.composite
def user_context(draw):
    """Generate a user context with various states."""
    return {
        'user_id': draw(st.uuids()).hex,
        'has_active_session': draw(st.booleans()),
        'previous_permission_state': draw(st.sampled_from([
            'not_requested',
            'denied',
            'granted'
        ])),
        'app_state': draw(st.sampled_from([
            'foreground',
            'background'
        ]))
    }


class MockLocationTracker:
    """Mock location tracker to simulate location tracking functionality."""
    
    def __init__(self):
        self.is_tracking = False
        self.tracking_enabled = False
        self.permission_granted = False
        self.last_location = None
        self.update_count = 0
    
    def grant_permission(self):
        """Simulate granting location permission."""
        self.permission_granted = True
        return True
    
    def enable_tracking(self):
        """Enable location tracking if permission is granted."""
        if self.permission_granted:
            self.tracking_enabled = True
            self.is_tracking = True
            return True
        return False
    
    def start_tracking(self):
        """Start location tracking."""
        if self.tracking_enabled and self.permission_granted:
            self.is_tracking = True
            return True
        return False
    
    def stop_tracking(self):
        """Stop location tracking."""
        self.is_tracking = False
        return True
    
    def update_location(self, location):
        """Update current location."""
        if self.is_tracking and self.permission_granted:
            self.last_location = location
            self.update_count += 1
            return True
        return False
    
    def get_tracking_state(self):
        """Get current tracking state."""
        return {
            'is_tracking': self.is_tracking,
            'tracking_enabled': self.tracking_enabled,
            'permission_granted': self.permission_granted,
            'update_count': self.update_count
        }


class TestLocationPermissionProperties:
    """Property-based tests for location permission functionality."""
    
    @settings(max_examples=100)
    @given(event=permission_grant_event())
    def test_property_18_location_permission_enables_tracking(self, event):
        """
        Feature: buyu-walking-app, Property 18: 位置权限启用
        Validates: Requirements 4.2
        
        Property: For any user permission grant event, when the user grants 
        location permission, the system SHALL enable location tracking functionality.
        
        This tests that:
        1. When permission is granted, tracking can be enabled
        2. The tracking functionality becomes available
        3. The system can start receiving location updates
        """
        # Arrange: Create a location tracker
        tracker = MockLocationTracker()
        
        # Verify initial state - tracking should not be enabled
        initial_state = tracker.get_tracking_state()
        assert not initial_state['tracking_enabled'], \
            "Tracking should not be enabled before permission is granted"
        assert not initial_state['permission_granted'], \
            "Permission should not be granted initially"
        
        # Act: Grant permission (simulating user granting permission)
        permission_result = tracker.grant_permission()
        
        # Assert: Permission should be granted
        assert permission_result, "Permission grant should succeed"
        assert tracker.permission_granted, \
            "Permission granted flag should be set to True"
        
        # Act: Enable tracking after permission is granted
        enable_result = tracker.enable_tracking()
        
        # Assert: Tracking should be enabled
        assert enable_result, "Enabling tracking should succeed after permission is granted"
        
        final_state = tracker.get_tracking_state()
        assert final_state['tracking_enabled'], \
            "Tracking functionality should be enabled after permission is granted"
        assert final_state['permission_granted'], \
            "Permission should remain granted"
        
        # Verify that tracking can actually start
        start_result = tracker.start_tracking()
        assert start_result, "Starting tracking should succeed when enabled"
        assert final_state['is_tracking'], \
            "Tracking should be active after starting"
    
    @settings(max_examples=100)
    @given(
        event=permission_grant_event(),
        location=st.tuples(
            st.floats(min_value=-90, max_value=90),  # latitude
            st.floats(min_value=-180, max_value=180),  # longitude
            st.floats(min_value=0, max_value=100)  # accuracy
        )
    )
    def test_property_18_granted_permission_allows_location_updates(self, event, location):
        """
        Feature: buyu-walking-app, Property 18: 位置权限启用
        Validates: Requirements 4.2
        
        Property: For any granted permission and any valid location data,
        the system SHALL be able to receive and process location updates.
        
        This tests that after permission is granted:
        1. Location updates can be received
        2. Location data can be stored
        3. The system tracks the number of updates
        """
        # Arrange
        tracker = MockLocationTracker()
        lat, lon, accuracy = location
        
        # Act: Grant permission and enable tracking
        tracker.grant_permission()
        tracker.enable_tracking()
        tracker.start_tracking()
        
        # Create location data
        location_data = {
            'latitude': lat,
            'longitude': lon,
            'accuracy': accuracy
        }
        
        # Act: Update location
        update_result = tracker.update_location(location_data)
        
        # Assert: Location update should succeed
        assert update_result, \
            "Location update should succeed when permission is granted and tracking is active"
        assert tracker.last_location == location_data, \
            "Location data should be stored correctly"
        assert tracker.update_count == 1, \
            "Update count should be incremented"
        
        # Test multiple updates
        for i in range(5):
            tracker.update_location(location_data)
        
        assert tracker.update_count == 6, \
            "Update count should reflect all updates"
    
    @settings(max_examples=100)
    @given(context=user_context())
    def test_property_18_permission_state_consistency(self, context):
        """
        Feature: buyu-walking-app, Property 18: 位置权限启用
        Validates: Requirements 4.2
        
        Property: For any user context, when permission is granted,
        the tracking enabled state should be consistent with permission state.
        
        This tests the consistency between permission state and tracking capability.
        """
        # Arrange
        tracker = MockLocationTracker()
        
        # Set up initial state based on context
        if context['previous_permission_state'] == 'granted':
            tracker.grant_permission()
            tracker.enable_tracking()
        
        # Act: Grant permission (or re-grant)
        tracker.grant_permission()
        
        # Assert: Permission should be granted
        state = tracker.get_tracking_state()
        assert state['permission_granted'], \
            "Permission should be granted after grant operation"
        
        # Act: Try to enable tracking
        enable_result = tracker.enable_tracking()
        
        # Assert: Tracking should be enabled successfully
        assert enable_result, \
            "Tracking should be enabled when permission is granted"
        
        final_state = tracker.get_tracking_state()
        assert final_state['tracking_enabled'], \
            "Tracking enabled state should be True when permission is granted"
        
        # Verify consistency: if permission is granted, tracking can be enabled
        assert final_state['permission_granted'] == True, \
            "Permission granted should be True"
        assert final_state['tracking_enabled'] == True, \
            "Tracking enabled should be True when permission is granted"
    
    @settings(max_examples=100)
    @given(
        grant_events=st.lists(
            permission_grant_event(),
            min_size=1,
            max_size=10
        )
    )
    def test_property_18_multiple_grant_events_idempotent(self, grant_events):
        """
        Feature: buyu-walking-app, Property 18: 位置权限启用
        Validates: Requirements 4.2
        
        Property: For any sequence of permission grant events,
        granting permission multiple times should be idempotent -
        the tracking functionality should remain enabled.
        
        This tests that:
        1. Multiple grant operations don't break the system
        2. Tracking remains enabled after multiple grants
        3. The system state is stable
        """
        # Arrange
        tracker = MockLocationTracker()
        
        # Act: Grant permission multiple times
        for event in grant_events:
            grant_result = tracker.grant_permission()
            assert grant_result, "Each grant operation should succeed"
        
        # Assert: Permission should still be granted
        assert tracker.permission_granted, \
            "Permission should be granted after multiple grant operations"
        
        # Act: Enable tracking
        enable_result = tracker.enable_tracking()
        
        # Assert: Tracking should be enabled
        assert enable_result, \
            "Tracking should be enabled after multiple grant operations"
        
        state = tracker.get_tracking_state()
        assert state['tracking_enabled'], \
            "Tracking should be enabled and stable"
        assert state['permission_granted'], \
            "Permission should remain granted"
    
    @settings(max_examples=100)
    @given(
        event=permission_grant_event(),
        num_locations=st.integers(min_value=1, max_value=50)
    )
    def test_property_18_continuous_tracking_after_permission(self, event, num_locations):
        """
        Feature: buyu-walking-app, Property 18: 位置权限启用
        Validates: Requirements 4.2
        
        Property: For any granted permission and any number of location updates,
        the system SHALL continuously track location as long as permission is granted.
        
        This tests that:
        1. Tracking continues for multiple updates
        2. Each update is processed correctly
        3. The system maintains tracking state
        """
        # Arrange
        tracker = MockLocationTracker()
        
        # Act: Grant permission and start tracking
        tracker.grant_permission()
        tracker.enable_tracking()
        tracker.start_tracking()
        
        # Assert: Initial state
        assert tracker.is_tracking, "Tracking should be active"
        
        # Act: Send multiple location updates
        for i in range(num_locations):
            location = {
                'latitude': 39.9042 + (i * 0.0001),
                'longitude': 116.4074 + (i * 0.0001),
                'accuracy': 10.0
            }
            update_result = tracker.update_location(location)
            
            # Assert: Each update should succeed
            assert update_result, \
                f"Location update {i+1} should succeed when tracking is active"
            assert tracker.is_tracking, \
                f"Tracking should remain active after update {i+1}"
        
        # Assert: Final state
        final_state = tracker.get_tracking_state()
        assert final_state['is_tracking'], \
            "Tracking should still be active after all updates"
        assert final_state['update_count'] == num_locations, \
            f"Should have processed {num_locations} updates"
        assert final_state['permission_granted'], \
            "Permission should remain granted throughout"
